John Edgar Hoover (January 1, 1895 – May 2, 1972) was an American law enforcement administrator who served as the fifth and final director of the Bureau of Investigation and the first director of the Federal Bureau of Investigation. President Calvin Coolidge first appointed Hoover as director of the BOI, the predecessor to the FBI, in 1924. After 11 years in the post, Hoover became instrumental in founding the FBI in June 1935, where he remained as director for an additional 37 years until his death in May 1972 – serving a total of 48 years leading both the BOI and the FBI under eight presidents.
Hoover expanded the FBI into a larger crime-fighting agency and instituted a number of modernizations to policing technology, such as a centralized fingerprint file and forensic laboratories. Hoover also established and expanded a national blacklist, referred to as the FBI Index or Index List.
Later in life and after his death, Hoover became a controversial figure as evidence of his secretive abuses of power began to surface.